Various systems are used to mount spinning rotors in open-end spinning devices. The rotor shaft of the spinning rotor may be directly mounted. For this purpose, a so-called pivot bearing can be used. However, indirect bearings are also known, in which the rotor shaft is mounted in support discs, the support discs in turn being able to be mounted by means of a pivot bearing. A support disc bearing, in comparison to a direct bearing with pivot bearings, has a longer service life, as the support discs, at the same rotational rotor speed, are operated at a lower rotational speed because of the transmission ratio between the rotor shaft and the support discs. However, the construction of a support disc bearing in comparison to a direct bearing is relatively complex and therefore gives rise to high production costs.
German Patent Publication DE 44 26 202 A1 discloses a support disc bearing for an open-end spinning device with a spinning rotor. The rotor shaft of the spinning rotor is driven by a tangential belt and is mounted in the wedge gap of two support disc pairs. Each support disc pair forms its own wedge gap. The support disc pairs are spaced apart from one another in the axial direction of the rotor shaft, so two support points are available for the rotor shaft. A respective support disc of a support disc pair is mounted by means of a bearing arrangement, which comprises a rotatable bearing axle with positioning means, rolling bearings, a spring sleeve connected between the rolling bearings as well as a bearing housing, on a bracket arranged on the rear of the rotor housing. The support discs are in each case attached by means of a press fit on the ends of the rotatable bearing axle. The support discs have a base body made of aluminium and a resilient plastics material raceway on the periphery of the base body. The plastics material raceway is necessary for damping purposes.
German Patent Publication DE 102 00 743 A1 discloses a support disc made of aluminium with a running surface made of plastics material, for example polyurethane or rubber. The running coating of the support disc is applied to the base body by means of injection molding. The base body may be produced by turning from a solid material. Bores are introduced in an additional working step. This means a high manufacturing outlay. It is also known to produce the aluminium body by extrusion. The manufacturing outlay is reduced by this but the aluminium body cannot be produced with the required fitting precision, so the base body generally has to be reworked by machining.
European Patent Publication EP 1 852 530 A1 also discloses a support disc for a rotor bearing of an open-end spinning device. The possibility of the base body also being able to be produced from plastics material is described. However, it has been shown that the support disc with a base body made of plastics material cannot be reliably applied to a bearing axle or bearing pins, because the plastics material starts to flow when there are pressing forces. In other words, a plastic deformation of the plastics material takes place, which makes a reliable hold impossible. In order to improve the seat on the bearing pin, it is therefore proposed that after the production of the plastics material base body, a bush comprised of metal is inserted into its hub.